Category: Projects

I built my first cMoy earlier this year, and it came out really great for my first attempt at building a headphone amp. The only problem was that it’s a poor match for the headphones I use. My headphones are all efficient low-impedance models (Grado, Ultrasone) that don’t require a lot of voltage. What they need is more current. The basic cMoy design doesn’t provide this, at least not with the OPA2132A OpAmp. I soon learned though that several DIYers have built similar “cMoy-esque” amps based on the circuit used in Grado’s RA1 headphone amplifier, which uses an NJM4556 (aka JRC4556) OpAmp, good for 70ma of current per channel. I decided to try building one, and I wanted it to be a little different. So I built it in a cigar box.

There was quite a bit of drilling and cutting involved, and I destroyed a couple boxes in the process. The volume knob is installed where the cigar maker’s medallion was previously located, which had their logo. For the circuit, I took some ideas from both the cMoy and the RA1 clones. I used some pretty high-end hardware, such as the Neutrik locking 1/4″ jack. It wasn’t because I thought it was necessary, but because it was easy to mount to the cigar box.

The result? Not very good. It’s unique, and looks interesting, but it doesn’t work very well. I ended up building two of them, and both are very noisy. Copper shielding on the second build helped, but not a lot. It might be all of the wiring needed to connect everything, or just the result of a poorly engineered DIY project based around a potentially “cranky” OpAmp, but it just isn’t a great amp. So I’ve kept the second one as a “show piece” while the first gets picked away at for spare parts. Even though it was ultimately a failed project, I’m glad I attempted it. For my next headphone amp, I’ll be using a professionally-engineered and designed circuit based around a PCB which should help ensure success.

I’m a big fan of the Playstation video game consoles, so when I learned about the PS2X library by Bill Porter, I had to try it out. PS2X makes it easy to interface Arduino microcontrollers with Playstation 2 controllers. After wiring everything up and testing it with the sample program, I set out to find something more interesting to do with it. The result is a stepper motor that is controlled by the Sony controller. Here’s a video of it in action:

Intro

At some point while researching microcontroller projects, I came across several people who had used Arduinos and PICs to drive analog panel meters so they would display computer stats such as CPU load, memory usage, etc. It immediately struck me as something I just had to do. Here it is. My PC meter uses an Arduino microcontroller and receives the stats from a .NET Framework application I wrote in C#.Net. It’s housed in a plastic enclosure and looks quite professional IMHO. It was a fun project, and something I think most any computer/electronics geek would enjoy. I love mine, and I look forward to building more.

Oftentimes, I find myself going to my parents’ house or a friend’s place to build or repair something, and I have nothing to put my larger tools in. As a result, my drill, saw, clamps and other large items end up either laying on the floor of my truck or stuffed into whatever cardboard box I found laying around. If I had a large, sturdy box to throw this stuff in, it would make these trips much more convenient and I would spend less time loading and unloading my tools and more time working. So when I saw Len Cullum’s Japanese Toolbox project in MAKE 34, I knew I had found my solution.

I’m planning an LED floodlight project that will use a lot of square 4-pin LEDs, aka SuperFlux or “Piranha” LEDs. I hadn’t had a chance to use these type of LEDs until now, so after receiving my order this week I immediately went to work on trying them out. This won’t be a very technical review, just a quick look at the specs and my experience with testing the LEDs and what I thought of them.